I am suspecting the high side and low side FET’s turned on at the same time, in either leg of the H bridge or both resulting in pretty much a direct short across the rail. I am not sure why your drivers passed. I haven’t tried anything yet. It is worthwhile to investigate. The PIC outputs are in the high impedance state while configuring the PWM module and the output drivers are enabled afterwards. A fuse isnt a bad idea but sometimes they are not fast enough. I have had the circuit working just fine and my code seems to work like it should, I could run the motor at different duty cycles and different frequencies.
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This protection mechanism is best implemented at the driver IC-Mosfet’s gate interface. Futterama Member Feb 7, I haven’t tried anything yet. Small motor circuits usually can get away with this.
You can always “deadbug” a resistor across G-S. It might be difficult to control the power up and power down phases so you might want to see if your application can tolerate those 0. You also cet want to kill the drives for all four transistors before you actually power down the PIC and the driver chips. That might prevent another blowout while you are doing the initial testing. It is worthwhile to investigate. Media New media New comments Search media. I am 44424 sure why your drivers passed.
Take a look and see what you can find out. You must log in or register to reply here. That would help prevent blowout from false turn on no matter how it occurred power up, power down, bad dead time setting, any false 44224.
It seems to me that k is fine, the gates should discharge real fast when power is removed with k pulldown and about pF MOSFET input capacitance.
Perhaps you need a better startup sequence. Forums New posts Search forums.
I supose you could just divide the 12 volts down, but that will slow it 44224 a bit so you would need to be careful on reversals. Click here to register now. Any idea what went wrong? Usually the power supply has enough capacitance to absorb the spike. If you want to use 1 ohm resistors that should be ok too as you can change them later once everything is working.
Did ret try the scope and resistors yet? Electro Tech is an online community with overmembers who enjoy talking about and building electronic circuits, projects and gadgets.
If they have a little internal resistance though that helps too. When building custom H bridges I always add some logic to prevent such situations happening i.
TSM 4424 CS
Yeah, I’m only applying PWM to the lowside FETs, the highside FETs are not modulated so the deadtime og dead-band delay is when the motor should change direction and this can’t be what happens here. In the end, it will be far cheaper and easier than replacing transistors and ICs.
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A quick scan on the TC datasheetdoes not 444 that feature. Thread starter Futterama Start date Feb 6, These are mounted on a heatsink and are electrically isolated using thermal pads and nylon washers for the screws. And real good idea to put a scope over the resistor to look for spikes.